Using a patch with DOS line endings

[Bruno Wolff III]

I have a patch for a source file that has DOS line endings and %patch 
strips the \r characters causing the patch to fail while suggesting the 
use of the --binary option. However the %patch macro will not accept 
the binary option.

Is there an easy way to use a patch with DOS line endings or am I going 
to need to convert the fix to unix line endins in prep, before applying 
the patch?